EP4338255A1 - Machine électrique à géométrie de stator variable configurée pour une perte de puissance réglable - Google Patents

Machine électrique à géométrie de stator variable configurée pour une perte de puissance réglable

Info

Publication number
EP4338255A1
EP4338255A1 EP21726079.3A EP21726079A EP4338255A1 EP 4338255 A1 EP4338255 A1 EP 4338255A1 EP 21726079 A EP21726079 A EP 21726079A EP 4338255 A1 EP4338255 A1 EP 4338255A1
Authority
EP
European Patent Office
Prior art keywords
stator
vehicle
electric machine
reconfiguration device
control unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21726079.3A
Other languages
German (de)
English (en)
Inventor
Johan Lindberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Volvo Truck Corp
Original Assignee
Volvo Truck Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Volvo Truck Corp filed Critical Volvo Truck Corp
Publication of EP4338255A1 publication Critical patent/EP4338255A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/18—Propelling the vehicle
    • B60W30/18009—Propelling the vehicle related to particular drive situations
    • B60W30/18109—Braking
    • B60W30/18127—Regenerative braking
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/12—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries responding to state of charge [SoC]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/40—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for controlling a combination of batteries and fuel cells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L7/00—Electrodynamic brake systems for vehicles in general
    • B60L7/02—Dynamic electric resistor braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/08—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of electric propulsion units, e.g. motors or generators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/18—Propelling the vehicle
    • B60W30/188—Controlling power parameters of the driveline, e.g. determining the required power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/02—Details of the magnetic circuit characterised by the magnetic material
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/14—Stator cores with salient poles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/0094—Structural association with other electrical or electronic devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/006—Structural association of a motor or generator with the drive train of a motor vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2200/00—Type of vehicles
    • B60L2200/36—Vehicles designed to transport cargo, e.g. trucks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B60L2240/12—Speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/425—Temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/545—Temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/60—Navigation input
    • B60L2240/64—Road conditions
    • B60L2240/642—Slope of road
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/70—Interactions with external data bases, e.g. traffic centres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2260/00—Operating Modes
    • B60L2260/40—Control modes
    • B60L2260/44—Control modes by parameter estimation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2300/00—Indexing codes relating to the type of vehicle
    • B60W2300/12—Trucks; Load vehicles
    • B60W2300/125—Heavy duty trucks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2556/00—Input parameters relating to data
    • B60W2556/45—External transmission of data to or from the vehicle
    • B60W2556/50—External transmission of data to or from the vehicle of positioning data, e.g. GPS [Global Positioning System] data
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2900/00—Indexing codes relating to the purpose of, or problem solved of road vehicle drive control systems not otherwise provided for in groups B60W30/00
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
    • H02K2213/09—Machines characterised by the presence of elements which are subject to variation, e.g. adjustable bearings, reconfigurable windings, variable pitch ventilators

Definitions

  • the present disclosure relates to heavy-duty vehicles such as semi-trailer vehicles for cargo transport, and in particular to electrically powered vehicles.
  • heavy-duty vehicles such as semi-trailer vehicles for cargo transport, and in particular to electrically powered vehicles.
  • the invention will be described mainly with respect to semi-trailer vehicles and trucks, the invention is not restricted to this particular type of vehicle but may also be used in other types of vehicles.
  • a heavy-duty vehicle such as a truck or semi-trailer vehicle, normally comprises a service brake system based on friction brakes.
  • Friction brakes such as disc brakes or drum brakes, are highly efficient in generating braking torque.
  • brake fading may occur, which is why friction brakes are not suitable for prolonged periods of use that may, e.g., occur when driving downhill for an extended period of time.
  • Brake fading is caused by a build-up of heat in the braking surfaces and leads to significantly reduced braking capability.
  • heavy-duty vehicles often comprise auxiliary brakes capable of endurance braking, such as engine brakes and various retarder systems.
  • An electric machine can also be used to slow down a vehicle.
  • the electric machine may then act as a generator which converts the kinetic energy from the vehicle into electrical energy.
  • This electrical energy can be fed to an energy storage system (ESS) such as a rechargeable battery or the like, resulting in an overall increase in energy efficiency of the vehicle.
  • ESS energy storage system
  • Surplus energy from regenerative braking can also be fed to a brake resistor where it is converted into heat.
  • the electric machine comprises a stator and a rotor separated by an air gap, where the stator comprises a stator reconfiguration device arranged to modify a magnetic property of the material in the stator.
  • the stator is arranged to be mechanically reconfigurable by the stator reconfiguration device to allow control of magnetic flux in the air gap.
  • This configuration allows a control unit arranged external to the electric machine to adjust the power losses of the electric machine (EM) to a desired power loss setting. If there is ample room in an energy storage system (ESS), then the power losses can be reduced down to a minimum in order to, e.g., recuperate as much energy as possible during braking. However, if the energy storage system is about to reach full state of charge, then the power losses can be increased in order to reduce the energy output from the electric machine during braking.
  • the mechanical arrangements disclosed herein can be adjusted regularly by an actuator controlled by a control unit.
  • the stator is preferably axially fixed with respect to the rotor. This allows for a more robust actuator arrangement which can be used to adjust power losses in the electric machine in a more reliable manner compared o the case where the stator is arranged movable in the axial direction with respect to the rotor.
  • This proposed electric machines allow for regulating the output energy during endurance braking by a heavy-duty vehicle dynamically to match the energy absorption capabilities of the energy storage system of the vehicle.
  • the endurance capability of the vehicle is extended, which is an advantage.
  • the regulation of efficiency level can be performed in real-time, or in a predictive manner to ensure that both current and future endurance braking capability of the vehicle is satisfactory. If the ESS is in a state where it can absorb energy then the EM is configured to output current which can be used, e.g., to replenish batteries in the ESS.
  • the energy output from the EM can be reduced by increasing the power loss level at which the EM is operating, which then instead increases the heat generation in the EM. It is an advantage to be able to adjust EM energy output in this manner to facilitate endurance braking, since the energy absorption demands on other vehicle components can be reduced, leading to a less complicated and more cost-effective overall vehicle energy system. Also, since the efficiency level of the EM is modulated in dependence of driving scenario, there is no significant performance penalty on the energy efficiency of the vehicle.
  • the stator reconfiguration device comprises a first section and second sections formed in different materials, where the different materials have different magnetic permeability properties, such that an orientation of the stator reconfiguration device relative to the stator influences the magnetic property of the stator.
  • the first section can for instance be formed in a material with high magnetic permeability such as soft magnetic composite or laminated magnetic steel, and where the second section which is formed in a low magnetic permeability material such as copper or aluminum.
  • the stator reconfiguration device is a rod extending in a longitudinal direction axially along the stator, where the rod is axially divided into first and second sections, and where the two sections are associated with different magnetic permeabilities.
  • the stator reconfiguration device can then be rotatably mounted about the longitudinal axis to allow control of the magnetic flux in the air gap by rotation of the stator reconfiguration device.
  • This version of the stator reconfiguration device is also relatively easy to implement in a reliable and robust manner and has been found to yield good results in terms of magnetic flux control.
  • the stator reconfiguration device is a rod extending in a longitudinal direction axially along the stator, where the rod is divided into first and second sections by a plane extending transversal to the longitudinal direction of the rod, where the two sections are associated with different magnetic permeabilities, and where the stator reconfiguration device is slidably mounted in the axial direction relative to the stator to allow control of magnetic flux in the air gap by longitudinal displacement of the rod.
  • the stator reconfiguration device comprises one or more conduits for passing a cooling medium through the stator reconfiguration device. These conduits improve the cooling capacity of the electric machine, and therefore allows for higher currents to pass through the components of the electric machine. The high currents, in turn, means that more power loss can be supported, which is an advantage.
  • the stator reconfiguration device comprises at least a first section and a second section formed in different materials, where the different materials have respective high and low relative magnetic permeability properties, and where the one or more conduits are arranged in the section associated with the low magnetic permeability property. This way the conduits are arranged where they are needed the most, i.e. , in a location where heat generation can be expected.
  • the electric machine comprises a stator geometry control unit arranged to control the orientation of the stator reconfiguration device based on a received control signal.
  • Figure 1 shows an example heavy-duty vehicle
  • Figure 2 schematically illustrates an electric machine control system
  • Figures 3-4 show example stator reconfiguration devices
  • Figures 5A-D illustrate impact on magnetic flux by stator reconfiguration
  • Figure 6 illustrates energy consumption by a vehicle along a route
  • Figure 7 is a signaling chart illustrating messaging in a control system
  • Figure 8 is a flow chart illustrating a method
  • Figure 9 schematically illustrates a control unit
  • Figure 10 shows an example computer program product
  • Figure 11 shows an example electric machine.
  • FIG 1 illustrates an example heavy-duty vehicle 100 for cargo transport.
  • the vehicle combination 100 comprises a truck or towing vehicle configured to tow a trailer unit in a known manner, e.g., by a fifth wheel connection.
  • a heavy-duty vehicle is taken to be a vehicle designed for the handling and transport of heavier objects or large quantities of cargo.
  • a heavy-duty vehicle could also be a vehicle designed for use in construction, mining operations, and the like.
  • the techniques and devices disclosed herein can be applied together with a wide variety of electrically powered vehicle units, not just that exemplified in Figure 1.
  • the techniques disclosed herein are also applicable to, e.g., rigid trucks and multi-trailer electric heavy-duty vehicles comprising one or more dolly vehicle units.
  • the vehicle 100 is an electrically powered vehicle comprising one or more electric machines (EM) 110.
  • the one or more EMs are arranged to generate both positive and negative torque, i.e., to provide both propulsion and braking of the vehicle 100.
  • the vehicle 100 also comprises an energy storage system (ESS) 120 configured to power the one or more EMs.
  • the ESS 120 may comprise a battery pack and potentially also a fuel cell (FC) stack arranged to generate electrical energy from a hydrogen storage tank on the vehicle 100 (not shown in Figure 1).
  • the ESS optionally also comprises a brake resistance arranged to dissipate surplus energy which the electrical energy storage devices on the vehicle 100 cannot accommodate.
  • a vehicle control unit 130 is arranged to monitor and control various vehicle operations and functions.
  • the vehicle control unit is, e.g., arranged to monitor and control the ESS 120 as well as the one or more EMs 110, and optionally also the operation of the FC stack.
  • the vehicle control unit 130 may also comprise higher layer control functions such as vehicle route planning and may have access to geographical data comprising height profiles of different planned vehicle routes and the like, as well as positioning data indicating a current location of the vehicle 100, which can be determined from, e.g., a global positioning system (GPS) receiver.
  • GPS global positioning system
  • the vehicle 100 optionally comprises a wireless communications transceiver arranged to establish a radio link 140 to a wireless network 150 comprising a remote server 160.
  • the control unit 130 may access the remote server 160 for uploading and downloading data such as the geographical data mentioned above comprising height profiles of different planned vehicle routes.
  • the vehicle 100 may store measurement data such as amounts of regenerated energy by the one or more EMs 110 at various geographical locations an along different vehicle routes in local memory or at the remote server 160.
  • the vehicle control unit 130 may also query the remote server for information about previously experienced amounts of regenerated energy, and/or temperature increases in various vehicle components along a given route, by the same vehicle or by some other vehicle having travelled along (parts of) the same route.
  • the vehicle control unit 130 may furthermore be arranged to obtain data indicative of an expected rolling resistance for a given route, either from manual configuration or remotely from the remote server 160.
  • the rolling resistance of the vehicle 100 will affect the energy consumption of the vehicle as it traverses a route. For instance, a gravel road is likely to require more energy compared to a more smooth asphalt freeway. Also, friction and air resistance will reduce the requirements on generating negative torque during downhill driving.
  • the EMs 110 on the vehicle 100 may, as mentioned above, be used to generate braking torque. Electrical energy from the EMs generated during braking can then be fed to the ESS as long as the ESS can absorb the power, resulting in recuperated energy and a more energy efficient vehicle operation, which is an advantage. However, when the batteries of the ESS are fully charged, no more energy can be absorbed. Furthermore, there may be a limit on maximum current or voltage that can be fed to the batteries of the ESS when charging.
  • a brake resistor also has a maximum amount of power it can absorb since it will eventually get too hot. Furthermore, there is normally a peak power capability of the brake resistor, i.e. , there may be a limit on maximum current or voltage that can be fed to the brake resistor.
  • the magnetic flux through a surface is the surface integral of the normal component of the magnetic field B over that surface. It is usually denoted ⁇ or ⁇ B.
  • the SI unit of magnetic flux is the Weber (Wb; in derived units, volt-seconds), and the CGS unit is the Maxwell.
  • Magnetic permeability is a measure of magnetization that a material obtains in response to an applied magnetic field. Permeability is typically represented by the Greek letter ⁇ . The reciprocal of magnetic permeability is magnetic reluctivity. In SI units, permeability is measured in Henries per meter (H/m), or equivalently in Newtons per ampere squared (N/A 2 ).
  • the permeability constant ⁇ 0 also known as the magnetic constant or the permeability of free space, is the proportionality between magnetic induction and magnetizing force when forming a magnetic field in a classical vacuum.
  • a closely related property of materials is magnetic susceptibility, which is a dimensionless proportionality factor that indicates the degree of magnetization of a material in response to an applied magnetic field.
  • An electrical motor is normally designed for operation at maximum efficiency, i.e., minimum power loss, meaning that maximum output power is generated during regenerative braking in order to recuperate as much energy as possible during downhill driving.
  • maximum efficiency i.e., minimum power loss
  • An electric machine used to generate braking torque which is operated in a less energy efficient mode of operation will generate more heat and less output current compared to an electric machine that is operated at maximum efficiency.
  • the generated torque by an EM is a function of the cross product between the current vector of the EM and the magnetic flux in the air gap formed between stator and rotor. It is therefore possible to adjust generated torque by altering the magnetic flux in the air gap.
  • This adjustment of magnetic flux can be achieved by mechanically modifying the geometry of the EM, whereby the power losses in the EM can be manipulated.
  • US 2008/0246430 A1 disclosed an EM design where the output current from the EM during regenerative braking can be adjusted by displacing the rotor axially relative to the stator. This axial adjustment has an impact on the magnetic flux in the air gap formed between stator and rotor, and therefore represents a way to adjust the power loss of the EM during operation.
  • the present disclosure instead proposes to adjust the geometry of the stator in order to change its magnetic properties during operation, and in this way control the power losses in the EM.
  • the power losses in the EM can be manipulated in close to real-time.
  • the present disclosure also builds on the previous work in the prior art by providing a control mechanism and a communications interface which allows the vehicle control unit 130 to balance electrical current output from the EM 110 during regenerative braking with a temperature increase in the EM during braking.
  • the control unit 130 is, by the proposed technique, able to balance EM temperature increase with ESS energy absorption capability during extended periods of down-hill driving, thereby providing an improved endurance braking capability for the heavy-duty vehicle 100 and thus a reduced need for over dimensioning the components of the vehicle 100.
  • the control signaling between the vehicle control unit and the one or more electric machines on the vehicle is versatile and allows for an efficient and robust control of the electric vehicle propulsion system.
  • control unit 130 also balances the current output of the EM during driving in a predictive manner. For instance, suppose a route involves an initial flat stretch of road followed by a long downhill section. The control unit may then mechanically and/or electrically configure the EM in an energy inefficient mode of operation to consume more power during the drive on the flat stretch of the route, in order to ensure sufficient endurance braking capability during the long downhill part of the route.
  • EM efficiency level is equivalent to the configuration of a power loss level of the EM.
  • the techniques disclosed herein are applicable also when no torque is generated by the EM, in which case a definition of efficiency may be cumbersome.
  • a power loss level is the same thing as an efficiency level, although the term power loss level is preferred when discussing EM operation involving zero torque.
  • FIG. 2 illustrates an example vehicle propulsion system 200 comprising an EM 110, an ESS 120 and a vehicle control unit 130.
  • the EM 110 here comprises an EM control unit 270 arranged to control the operation of an inverter 230 which drives the electric machine.
  • the EM is associated with an EM temperature 210, which may relate to, e.g., a temperature of the stator windings and/or to other components in the EM. It is appreciated that the different components of an electric machine are associated with a specification regarding maximum temperatures. If those temperatures are exceeded, then the respective EM components risk malfunction or will at least suffer an increased wear.
  • the EM control unit 270 is arranged to communicate with the vehicle control unit 130 over a control interface 135. Various control messages may be exchanged over this interface 135.
  • the vehicle control unit 130 may use the interface 135 to configure a degree of efficiency, or a power loss level of the EM subsystem 110.
  • the EM sub-system 110 may also use the interface 135 to report back capabilities to the vehicle control unit 130.
  • the vehicle control unit 130 may communicate with the EM subsystems and balance regenerative braking efficiency in dependence of their respective capabilities and energy absorption capabilities of the vehicle ESS 120.
  • the EM subsystem 110 may, as mentioned above, be operated at varying degrees of efficiency, using either mechanical adjustments in the EM or variation in the control of the EM drive circuit.
  • An EM used for propulsion of a vehicle 100 is normally operated at maximum efficiency, which means that a maximum output current always results from applying negative torque, in order to recuperate as much energy as possible.
  • the currents in the stator windings of the EM can be controlled such that this efficiency is reduced significantly.
  • this efficiency can be controlled by the control unit 130 in real time, or at least close to real time, in dependence of the energy efficiency capability of the EM 110 and in dependence of the energy absorption capability of the ESS 120.
  • control unit 130 can obtain both an energy efficient operation by the vehicle 100 by maximizing energy efficiency as long as the ESS 120 is able to absorb the generated output current during regenerative braking, and also an increased capability of endurance braking if needed, by reducing the efficiency of the EM 110, i.e. , increasing the EM power loss, thereby reducing output energy from the EM during regenerative braking and instead raising the internal temperature of the EM 110.
  • a power loss can even be configured at zero torque, in which case the EM start to act like a brake resistance which dissipates energy from the ESS.
  • an EM where the efficiency level is configurable in this manner also comprises a higher capacity cooling system, such as an oil-based cooling system with a sufficiently sized heat exchanger and fan.
  • a higher capacity cooling system such as an oil-based cooling system with a sufficiently sized heat exchanger and fan.
  • the higher the cooling capacity of the EM the less power efficient it can be for longer periods of time.
  • the EM can be designed to provide endurance braking for an unlimited duration of time, at least for certain vehicle maximum load and the like.
  • the endurance braking capability of the EM can be further increased if the techniques involving stator geometry reconfiguration is combined with the techniques involving control of stator winding currents. By balancing the two methods of EM power loss control, the rate of temperature increases in the EM for a given braking torque can be reduced.
  • the cooling of the EM can also be adjustable, e.g., by adjusting a fan speed or flow rate of cooling liquid to provide additional cooling when the EM is configured in an energy inefficient mode of operation, i.e. , at high power loss.
  • the control unit 130 is configured to control a variable cooling 280 of the EM 110 in dependence of the efficiency level at which the EM is configured, such that increased cooling is performed when the EM is operated in an energy inefficient mode of operation, that is, at a high power loss setting.
  • this cooling system can be combined with the mechanism for modify the magnetic properties of the stator, as will be discussed in more detail below.
  • the variable cooling 280 of the EM 110 can also be configured to operate in a predictive manner.
  • variable cooling system is operated in anticipation of an increase in temperature, e.g., if it is known that an endurance braking function of the vehicle 100 will be used in the near future, since there is a long downhill section of road up ahead of the vehicle along its planned route.
  • the ESS 120 of the vehicle propulsion system 200 comprises a battery pack 125 connected to an optional brake resistor 250 for dissipating surplus energy.
  • An optional FC stack 240 is also indicated as comprised in the ESS 120.
  • the ESS 120 is associated with a state of charge (SoC) 220 indicating, e.g., how much charge that is currently carried by the battery pack.
  • SoC state of charge
  • one or more components of the ESS 120 may also be associated with a temperature 260, where it is appreciated that some components may risk permanent damage or at least temporarily reduced function is overheated.
  • the temperature of the brake resistor 250 can be expected to vary with surplus energy. If it is used to dissipate large amounts of energy, then it may reach critical temperatures, which is of course undesired.
  • the FC stack 240 is normally difficult to turn off and re-start since it takes time to do this without damaging the FC stack. Thus, it is preferred to always generate some power by the FC stack 240, even if the ESS is close to full SoC and the vehicle is driving downhill.
  • One advantage of the techniques disclosed herein is that the efficiency level of the EM subsystem 110 can be configured at a constant power loss value corresponding to the minimum output power from the FC stack, thus compensating for the energy contribution by the FC stack.
  • An electric machine such as the EM 110, comprises a stator and a rotor which are separated by an air gap, where the rotor is arranged to rotate together with the motor axle.
  • the motor axle will be generally used as reference axis, and its extension direction will be referred to as the axial direction, denoted as A in the Figures.
  • the EMs considered herein have stators which are axially fixed with respect to the rotor, i.e. , the EMs discussed herein are different from the type of EMs discussed in US 2008/0246430 A1 where the rotor is axially displaced relative to the stator in order to control the efficiency of the electric machine.
  • the stators of the herein disclosed EMs comprise one or more stator reconfiguration devices which are arranged to modify a magnetic property of the stator.
  • the EMs differ from those discussed in US 2019/0207447 A1 where it is proposed to change the magnetic properties of the rotor instead of the stator to adjust EM efficiency and/or power loss level.
  • the stator 510 in the current proposal is mechanically reconfigurable by the stator reconfiguration device to allow control of magnetic flux in the air gap.
  • This mechanical reconfiguration of the stator can advantageously be combined with control of the stator winding currents in order to obtain an even better control of the power loss in the EM.
  • the electric machine 110 may, as shown in Figure 2, comprise a stator geometry control unit 290 arranged to control the physical orientation of the stator reconfiguration device based on a received control signal 295. This control signal 295 will then determine the current energy efficiency, i.e., the current power loss level at which the EM 110 is operating.
  • the EM 110 preferably also comprises a temperature sensor 210 arranged to measure a temperature of the stator reconfiguration device.
  • the EM control unit 270 may report current temperatures up to the vehicle control unit 130, which may adapt its control of the vehicle 100 in dependence of the temperatures of the stator reconfiguration devices on the vehicle 100. By allowing a controlled increase in temperature, more current can be allowed to flow, which results in increased power loss.
  • Figures 3 and 4 show two example stator reconfiguration devices 300, 400 which can be used to mechanically modify a magnetic property of the stator in the EM 110, e.g., its magnetic permeability in a certain place or the tendency for eddy currents to be generated at some location in the stator.
  • the stator reconfiguration devices are arranged to be at least partially embedded into the stator, where they may affect the magnetic flux in the stator.
  • Figure 11 shows an example EM 110 comprising a plurality of stator reconfiguration devices arranged axially (A) in the stator.
  • each of the stator reconfiguration devices 300, 400 comprises two different materials denoted M1 and M2, with different respective magnetic permeabilities, where it is appreciated that more than two materials can be used in the stator reconfiguration devices.
  • a stator reconfiguration device can be moved relative to the stator, and in this way change the magnetic properties of the stator, which in turn will have an impact on the power loss in the EM 110.
  • the stator reconfiguration device 300 in Figure 3 is arranged to be rotated about its longitudinal axis, as indicated by the arrow R, which will change the material configuration in the stator if the rotation is performed relative to the stator, i.e., with the stator in a fixed position.
  • the stator reconfiguration device 300 is in the form of a rod extending in a longitudinal direction axially A along the stator.
  • the rod is divided axially into first and second sections, where the two sections are associated with different magnetic permeabilities, and where the stator reconfiguration device 300 is rotatably mounted about the longitudinal axis to allow control of the magnetic flux in the air gap by rotation of the stator reconfiguration device 300.
  • the stator reconfiguration device 400 in Figure 4 is instead divided transversally to its longitudinal axis, such that the first material M1 forms one end of the rod and the other material M2 forms the opposite end of the rod. Wth this configuration, the axial position of the stator reconfiguration device 400 relative to the stator will affect the magnetic properties of the stator, and thus impact the power loss in the EM 110. In other words, the stator reconfiguration device 400 can be slided back and forth in the axial direction, in order to change the magnetic properties of the stator.
  • the stator reconfiguration device 400 may also be formed as a rod extending in the longitudinal direction axially A along the stator, where the rod is divided into first and second sections by a plane extending transversal to the longitudinal direction of the rod, and where the two sections are associated with different magnetic permeabilities.
  • the stator reconfiguration device 400 can be slidably mounted in the axial direction A relative to the stator 510 to allow control of magnetic flux in the air gap by longitudinal displacement of the rod.
  • the stator reconfiguration devices 300, 400 disclosed herein may comprise first and second sections formed in different materials M1, M2, where the different materials have different magnetic permeability properties, such that an orientation of the stator reconfiguration device 300, 400 relative to the stator influences the magnetic property of the stator.
  • the first section can be formed in a material with high magnetic permeability such as soft magnetic composite or laminated magnetic steel, and the second section can be formed in a low magnetic permeability material such as copper or aluminum.
  • high permeability materials are known, as well as other low permeability materials.
  • stator reconfiguration device 400 need not be shaped as a cylinder, since it does not rotate but slide relative to the stator.
  • a rectangular cross section shape would also be possible for instance, or any cross section shape which allows the stator reconfiguration device 400 to slide axially relative to the stator.
  • Figures 5A and 5B illustrate a practical example 500 of how the stator reconfiguration device 300 can be used to change the magnetic properties of the stator.
  • Figure 5A illustrates an EM comprising a stator 510 and a rotor 520 separated by an air gap 530, where a stator reconfiguration device 300 has been embedded into the stator radially outwards from the motor axle.
  • the stator reconfiguration device 300 has been arranged rotatably embedded into the stator outer hull, where about half of the rod is inside the hull of the stator 510, and about half of the rod is outside the hull.
  • the rod will present a different material to the stator interior.
  • the high magnetic permeability material M1 is presented towards the interior of the stator 510
  • the low magnetic permeability material M2 is instead presented towards the interior of the stator 510.
  • the effect on the magnetic flux in the air gap can be seen in the Figures from the insert scales: the magnetic flux in the air gap 530 is notably higher when the high magnetic permeability material M1 is presented towards the stator interior by the stator reconfiguration device 300 compared to when the material M2 is facing the interior of the stator.
  • the same effect can also be obtained if the stator reconfiguration device 400 is used instead and slided axially with respect to the stator, such that different magnetic permeability materials are embedded into the stator.
  • Figure 5C shows the stator reconfiguration device from Figure 5A without magnetic flux strength, and with flux direction indicated by the arrows.
  • Figure 5D shows the stator reconfiguration device from Figure 5B without magnetic flux strength, and with flux direction indicated by the arrows.
  • the stator reconfiguration device 300, 400 may also comprise one or more conduits 310 for passing a cooling medium through the stator reconfiguration device. These cooling conduits allow for an efficient cooling of the EM since they are arranged close to the location where heat will be generated when the EM is operating in an inefficient mode of operation associated with high power loss.
  • the cooling conduits are preferably formed in the low magnetic permeability material M2, where the need for cooling is the highest.
  • the stator reconfiguration device 300, 400 comprises first and second sections formed in different materials M1, M2, where the different materials have respective high and low relative magnetic permeability properties, and where the one or more conduits are arranged in the section associated with the low magnetic permeability property.
  • a vehicle control unit 130, 900 for controlling an EM 110 of a heavy-duty vehicle 100 comprises a stator 510 and a rotor 520 separated by an air gap 530, where the stator 510 comprises a stator reconfiguration device 300, 400 as discussed above arranged to modify a magnetic property of the stator, whereby the stator 510 is mechanically reconfigurable by the stator reconfiguration device 300, 400 to allow control of magnetic flux in the air gap.
  • the heavy-duty vehicle 100 also comprises an energy storage system (ESS) 120 as shown in Figure 2, connected to the EM 110.
  • ESS energy storage system
  • control unit 130, 900 comprises processing circuitry 910 configured to obtain S1 an energy absorption capability of the ESS 120, determine S2 an amount of regenerated energy by the EM 110 during braking, and configure S3 an efficiency level of the EM 110 in dependence of the energy absorption capability of the ESS 120 and the amount of regenerated energy by the EM 110 during braking, at least in part by reconfiguring the stator reconfiguration device 300, 400.
  • the processing circuitry 910 is configured to predict S22 an amount of regenerated energy from the EM 110 based on a planned route of the vehicle 100, and to control the stator reconfiguration device 300, 400 in dependence of the predicted amount of regenerated energy.
  • Figure 6 illustrates an example 600 of a height profile along a planned vehicle route (shown as a solid line).
  • the dashed line in Figure 6 illustrates an expected SoC along the same route for a nominal value of configured electric machine efficiency, i.e. , a given orientation of the stator reconfiguration device. It can be seen that the SoC decreases in uphill sections of the route and increases in downhill sections of the route. At the end of this route the expected SoC exceeds 100%, which is undesired.
  • the expected SoC in Figure 6 may be determined from the current energy absorption capability of the ESS and the expected energy generation from regenerative braking.
  • the estimated energy generation (in Joules and/or Watts) from regenerative braking in a given driving scenario for different power loss configurations can be tabulated beforehand by experimentation and/or mathematical analysis which may involve computer simulation.
  • additional advantages can be obtained if the energy generation in different operating conditions is logged, perhaps in collaboration with other vehicle via the remote server 160.
  • the accuracy of the estimated amount of energy that can be expected from regenerative braking in different driving conditions and with different energy efficiency settings of the EM systems on the vehicle 100 can be improved. For instance, if a given vehicle driving down a hill having a certain slope and carrying a given amount of cargo generates a certain amount of energy, then this amount and the driving conditions can be written to memory, and optionally communicated to the remote server 160. The next time the vehicle drives down a similar slope carrying a similar load, the estimate of generated energy will be more accurate. The vehicle may also download relevant data from the remote server 160 indicative of an expected behavior of the EM along some given route. Interpolation can of course be used to estimate energy generation for a scenario which resembles some already experienced scenarios.
  • the rolling resistance can, as mentioned above, also have an effect on the energy consumption of the EM as the vehicle 100 traverses a route.
  • the rolling resistance can often be accurately predicted based on information related to the road properties, such as if the road is a gravel road or a smooth freeway.
  • the rolling resistance is also at least partly a property of the vehicle 100, and its tyres.
  • the vehicle may upload the “ESS SoC profile” 620 corresponding to travelled routes to the remote server 160.
  • the remote server 160 can then store this information, an make it available for other vehicles.
  • a vehicle planning a transport mission can query the remote server 160 to see if an ESS SoC profile is available for the planned route. If this is the case, then the vehicle can download the SoC profile from the remote server and use this SoC profile to plan EM efficiency level configuration for the duration of the route his ensures that the vehicle maintains an endurance braking capability for the entire route.
  • the processing circuitry 910 is configured to send S32 a control signal comprising a requested power loss level to an EM control unit 270 arranged to control the position of the stator reconfiguration device 300, 400 in dependence of the requested power loss level.
  • the processing circuitry 910 is configured to receive S34 a power loss capability report from the EM control unit 270.
  • FIG. 8 shows a flow chart which summarizes some of the methods discussed herein.
  • a method performed in a vehicle control unit 130 for controlling an electric machine (EM) 110 of a heavy-duty vehicle 100 which comprises an energy storage system (ESS) 120 connected to the EM 110.
  • the method comprises obtaining S1 an energy absorption capability of the ESS 120.
  • This energy absorption capability of the ESS is likely to vary over time, and can be monitored by the control unit 130, e.g., by determining S11 a state of charge (SoC) 220 of a battery pack comprised in the ESS 120, by determining S12 a temperature of the battery pack comprised in the ESS 120, and/or determining S13 a temperature 260 of a brake resistor 250 comprised in the ESS 120.
  • SoC state of charge
  • Energy absorption capability in terms of power may be limited by an upper power limit which depends on the design of the ESS, i.e., the rating of the components comprised in the ESS.
  • the capability of the ESS in terms of power is normally also dependent on temperature. For instance, brake resistance temperature impacts energy absorption capability negatively, since a very hot braking resistance may not be able to absorb very much energy until it has cooled down again.
  • the energy absorption capability in terms of energy amount is often a linear function of state of charge, where a nearly fully charged battery pack cannot absorb so much energy, and a nearly empty battery pack is able to absorb a significant amount of energy.
  • a retarder is a device used to augment some of the functions of primary friction-based braking system, usually on heavy-duty vehicles.
  • Retarders serve to slow vehicles down or maintain a steady speed while traveling down a hill and help prevent the vehicle from "running away” by accelerating down the hill. They are not usually capable of bringing vehicles to a standstill, as their effectiveness diminishes as vehicle speed lowers. They are instead used as an additional "assistance” to slow vehicles, with the final braking done by a conventional friction braking system or a brake system based on electric machines. As the friction brake will be used less, particularly at higher speeds, their service life is increased.
  • the braking capability of a retarder system is a function of the state of the retarder, such as its temperature.
  • the method may furthermore comprise determining S14 a state, such as a temperature or other metric indicative of a braking capability, of a retarder system arranged to provide a braking torque to prevent acceleration by the heavy-duty vehicle 100.
  • a state such as a temperature or other metric indicative of a braking capability
  • Various retarder systems are known, such as water retarders and oil retarders.
  • An increased accuracy in determining the energy absorption capability of the ESS can be obtained if the behavior of the ESS is monitored during vehicle operation, and the dependence between energy absorption capability and vehicle component state is recorded. For instance, the effect of temperature on the behavior of the ESS can be monitored and a record of energy absorption capability can be maintained, which can then be consulted if an energy absorption capability is to be determined in the future. Data related to energy absorption capability of the ESS can also be communicated to the remote server 160, which may then construct a model of ESS energy absorption capability to be shared with other vehicles of the same type or comprising the same type of ESS.
  • the method also comprises determining S2 an amount of regenerated energy by the EM 110 during braking.
  • the amount of energy regenerated by the EM 110 during braking can of course be determined simply by measuring S21 the amount of regenerated energy by the EM 110. However, it is also possible to predict S22 the amount of regenerated energy from the EM 110 based on a planned route of the vehicle 100.
  • the methods may also comprise determining S23 a maximum amount of regenerated energy by the EM 110 based on a vehicle load and an endurance braking requirement of the vehicle 100.
  • the vehicle 100 may, e.g., be required to be able to limit speed when driving downhill for longer distances, i.e. , the vehicle may be associated with an endurance braking capability requirement. This requirement together with a minimum energy absorption capability of the vehicle ESS can be translated into a maximum allowable efficiency of the electric machines on the vehicle.
  • the required longitudinal torque can be expressed as where m GCW is the vehicle gross combination weight, a x,req is the required retardation, C d A ⁇ is the product of air drag coefficient C d and vehicle front area A ⁇ , ⁇ air represents air density, ⁇ x is the vehicle speed, g is the gravitational constant, C r is rolling resistance, and s is a slope percentage between 0 and 100.
  • the required torque for a planned route can be obtained for nominal value of air resistance (or air drag coefficient, front area etc.).
  • the required torque can in turn be used to determine the energy generation during downhill sections. In case the energy absorption capability of the ESS goes below the required level and/or if the capability of the EM in terms of minimum efficiency increases, then the vehicle control unit 130 may trigger a warning signal, or even prevent vehicle operation.
  • the method also comprises configuring S3 a power loss level or an efficiency level of the EM 110 in dependence of the energy absorption capability of the ESS 120 relative to the amount of regenerated energy by the EM 110 during braking.
  • This may, e.g., be achieved by configuring S31 the efficiency level of the EM 110 as a D/Q setpoint determined under constraints of a desired motor torque and power loss level, as was discussed in, e.g., GB 2477229 B and US 2017/0282751 A1, and/or by mechanically configuring the stator reconfiguration devices discussed above in connection to Figures 3, 4, 5A and 5B.
  • the vehicle control unit 130 balances the efficiency level of the electric machines on the vehicle 100 such that the amount of regenerated energy during downhill driving does not exceed the energy absorption capabilities of the vehicle ESS.
  • the efficiency level of the EM 110 may be expressed in terms of a power loss in absolute or relative terms.
  • An absolute measure of power loss may, e.g., be measured in Watts (W), while a relative power loss level may be measured, e.g., in terms of a percentage with respect to maximum efficiency. It is appreciated that the techniques disclosed herein are applicable also when no torque is generated by the EM, where the EM still can be configured to draw power from the ESS.
  • the technique of configuring a power loss level or an efficiency level of the EM 110 in dependence of the energy absorption capability of the ESS 120 may involve a model and a calculation method to optimize the power losses of a permanent magnet synchronous electric machine with respect to some target performance criteria.
  • the adjustment of efficiency level of an electric machine is a generally known technique and will therefore not be discussed in detail herein. We instead refer to examples from the literature for more details and implementation examples, e.g., GB2477229B and US 2017/0282751 A1.
  • the example circuit model and calculation method provide separation of the power losses associated with the winding power loss and core power losses for a machine, for different dc voltages and axle speeds.
  • the algorithm calculates the current set-points in direct and quadrature dimension ( i d , i q ) that provides a certain power loss for a given torque request, dc voltage U dc , maximum current I max and axle speed ⁇ .
  • the electric machine model is represented by the circuit model shown in Figure 10.
  • This model is an extension to the model provided by S. Morimoto, T. Ti, Y. Takeda, and T. Hirasa, in “Loss minimization control of permanent magnet synchronous motor drives,” IEEE Transactions on Industrial Electronics, vol. 41, pp. 511-517, Oct 1994.
  • the model comprises a leakage inductance L ⁇ , a mutual inductance: L m , and two resistances r and r c , where resistance r is associated with the C u -losses (electric machine variable losses) and the resistance r c is associated with the core losses in the electric machine.
  • e there is also a back-EMF denoted here by e which is associated with the permanent magnetic flux of the electric machine.
  • the voltage v is the applied voltage from the inverter, i.e. , the motor drive circuit.
  • subscript d denotes direct dimension
  • subscript q denotes quadrature dimension.
  • Electric machine axle speed is denoted by ⁇ and ⁇ generally denotes flux.
  • the electric torque T is given by the equation below, where ⁇ ⁇ denotes the airgap flux.
  • ⁇ ⁇ denotes the airgap flux.
  • the combination of setpoint currents i d and i q provides a degree of freedom to minimize the power loss in the machine for a certain torque.
  • ⁇ s d and ⁇ s q denotes direct and quadrature components of the stator flux
  • L d L m d + L ⁇
  • L q L m q + L ⁇ .
  • the optimization problem to be solved can be represented as where l b and u b are lower and upper bounds which can be configured according to any constraints in place on the EM state.
  • the non-linear non-equality constraints yield for motor mode of operation and the non-linear equality constraints are given by where and
  • FIG. 7 shows an example signaling diagram which illustrates the disclosed methods in terms of signaling over the interface 135 between vehicle control unit 130 and the EM subsystem control unit 270.
  • the EM subsystem control unit first reports a power loss capability to the vehicle control unit. Based on the capabilities of the EM sub- system the vehicle control unit 130 then uses the interface 130 to the EM control unit 270 to set a desired power loss. This configuration is then acknowledged by the EM control unit by means of a power loss status message. In this example, the temperature of the electric machine then increases. To protect the components of the EM subsystem from overheating, a new lower power loss capability is reported to the vehicle control unit over the interface. This new capability report may result in an updated power loss setting by the vehicle control unit.
  • the vehicle control unit 130 may respond to the new capability report in other ways. For instance, the vehicle control unit 130 may perform a different force allocation over the different vehicle motion support devices in order to reduce the torque requests on the EM subsystem reporting a reduced power loss capability. This way the vehicle control unit 130 can also balance energy dissipation over the whole vehicle combination.
  • Figure 4 illustrates an example operation of the signaling interface 135, shown in Figure 2, for exchanging data between the vehicle control unit 130 and the EM control unit 270, i.e. , a signaling interface arranged to carry a request from the vehicle control unit 130to the EM control unit 270 indicating a desired efficiency level for operation by the EM.
  • the methods may comprise sending S32 a requested power loss from the vehicle control unit 130 to the EM control unit 270.
  • This requested power loss may, as noted above, conveniently be defined relative to a nominal efficiency level or relative to some maximum obtainable efficiency level.
  • Figure 5 shows an example 500 where the desired power loss has been configured at 5kW. It is noted that this power loss is maintained for a wide range of desired motor torques and motor speeds.
  • the EM subsystem is even able to sustain a power loss at zero generated torque.
  • the EM subsystem may also assume a role similar to a braking resistance which can be used to dissipate energy even if no torque is generated by the electric machine.
  • the methods disclosed herein optionally also comprise sending S33 a power loss status report from the EM control unit 270 to the vehicle control unit 130.
  • This power loss status report may comprise information such as, e.g., a current setting of power loss, allowing the vehicle control unit to verify that a requested power loss is actually in effect.
  • the EM control unit may also be configured to send S34 a power loss capability report to the vehicle control unit 130, thus informing the vehicle control unit 130 about what ranges of power losses that can be supported currently.
  • This capability report may also comprise a prediction regarding a time period during which a current power loss can be sustained.
  • This prediction can, e.g., be based on a rate of increase in temperature of the electric machine, and possibly also on past experiences during similar operating conditions, of which data has been stored in memory.
  • the power loss capability report is optionally determined S35 based on a temperature level of the EM 110.
  • the method may comprise configuring S36 the efficiency level of the EM 110 in dependence of a minimum power output of an FC stack 240 in the vehicle 100.
  • the efficiency level of an electric machine is often a function of axle speed. Therefore, the method may also comprise configuring S37 a gear ratio associated with a transmission of the heavy-duty vehicle 100 in order to adjust the efficiency level of the EM.
  • FIG. 9 schematically illustrates, in terms of a number of functional units, the components of a control unit such as the ECU 101.
  • the control unit may implement one or more of the above discussed functions of the TSM, VMM and/or the MSD control function, according to embodiments of the discussions herein.
  • the control unit is configured to execute at least some of the functions discussed above for control of a heavy-duty vehicle 100.
  • Processing circuitry 910 is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g., in the form of a storage medium 920.
  • the processing circuitry 910 may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.
  • Figure 9 schematically illustrates a vehicle control unit 900 for controlling an electric machine 110 of a heavy-duty vehicle 100, where the heavy-duty vehicle comprises an energy storage system 120 connected to the EM 110.
  • the control unit 900 comprises processing circuitry 910 configured to obtain S1 an energy absorption capability of the ESS 120, determine S2 an amount of regenerated energy by the EM 110 during braking, and configure S3 an efficiency level of the EM 110 in dependence of the energy absorption capability of the ESS 120 and the amount of regenerated energy by the EM 110 during braking.
  • the storage medium 920 may store the set of operations
  • the processing circuitry 910 may be configured to retrieve the set of operations from the storage medium 920 to cause the control unit 101 to perform the set of operations.
  • the set of operations may be provided as a set of executable instructions.
  • the processing circuitry 910 is thereby arranged to execute methods as herein disclosed.
  • the storage medium 920 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.
  • the control unit 101 may further comprise an interface 930 for communications with at least one external device.
  • the interface 930 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline or wireless communication.
  • the processing circuitry 910 controls the general operation of the control unit 101, e.g., by sending data and control signals to the interface 930 and the storage medium 920, by receiving data and reports from the interface 930, and by retrieving data and instructions from the storage medium 920.
  • Other components, as well as the related functionality, of the control node are omitted in order not to obscure the concepts presented herein.
  • Figure 10 illustrates a computer readable medium 1010 carrying a computer program comprising program code means 1020 for performing the methods illustrated in Figure 8, when said program product is run on a computer.
  • the computer readable medium and the code means may together form a computer program product 1000.

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Abstract

L'invention concerne une machine électrique (110) pour un véhicule utilitaire lourd (100), la machine électrique comprenant un stator et un rotor séparés par un entrefer, le stator comprenant un dispositif de reconfiguration de stator agencé pour modifier une propriété magnétique du stator, le stator étant mécaniquement reconfigurable par le dispositif de reconfiguration de stator pour permettre la régulation du flux magnétique dans l'entrefer.
EP21726079.3A 2021-05-12 2021-05-12 Machine électrique à géométrie de stator variable configurée pour une perte de puissance réglable Pending EP4338255A1 (fr)

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JP2008259361A (ja) 2007-04-06 2008-10-23 Mitsuba Corp 電動車両用駆動装置
GB2477229B (en) 2011-03-25 2012-01-25 Protean Electric Ltd An electric motor arrangement and method of controlling thereof
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US10581287B2 (en) 2018-01-02 2020-03-03 GM Global Technology Operations LLC Permanent magnet electric machine with variable magnet orientation
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